1. Field of the Invention
The present invention is directed to portable and modular detection devices. In particular, the present invention is directed to portable and modular detection devices performing lock-in amplification.
2. Description of the Related Art
Recent advances in miniaturization, and particularly in the field of microelectro-mechanical structures (MEMS), have led to the development of microfluidic devices that are designed, in part, to perform a multitude of chemical and physical processes on a micro-scale. The attraction of these microsystems lies in the fact that miniaturization provides for substantial advantages in terms of cost, speed, the capability for easy automation, reproducibility, rapidity of analysis, and the need for only very small (μl) samples. As a consequence, microsystems in the form of microfluidic devices are becoming increasingly important in such diverse fields as DNA sequencing, immunochromatography, analysis and identification of explosives, chemical and biological warfare agents, and synthesis of chemicals and drugs.
Because only minute amounts of sample are required these microchemical analysis systems are particularly attractive for not only for rapid chemical analysis but also for the ability to analyze accurately a large number of samples in a short period of time. Unfortunately, prior art devices which are purported to be portable (handheld), modular, and reproducibly detect and measure low concentrations of analytes are not truly portable, modular, incapable of detecting and measuring low concentration of analytes, or a combination thereof.
For example, U.S. Pat. No. 6,998,598 discloses a modular optical detector system which asserts picomolar detection limits. In practice, however, the optical detector exhibits low signal to noise and is only useful in the nanomolar range. Further, the optical detector is not completely modular as only a select few components may be replaced by substantially similar components in a substantially similar location as the original component.
Thus, a need exists for portable and modular detection systems that reproducibly detect and measure low concentrations of chemicals conveniently, safely and quickly.